Their Greatest Mistake
by AutumnMoon12
Summary: *Based on the death of Barbra Gordon in her dream from B:TAS* It was their fault. They shouldn't have continued letting Hiro crime-fight, and now he was dead, and Tadashi loathed them now... It was all their fault... Rated T for mentions of blood, character death, and cause I'm paranoid. DISCLAIMER: I own nothing.


**A/N: Hey guys, welcome to my second story. This is based off of Barbra Gordon's dream in Batman: The Animated Series, the one where she dreamed about herself getting killed by Scarecrow, and her father blaming Batman for it.**

 ** _PLEEEAAASE READ! NOTES!:_ Also, let's say Tadashi is alive in this AU, and he somehow doesn't know about the team.**

Hiro glided through the cool night air on Baymax as his team followed the pair, though they seemed more slower and tired than usual. The night had been full of crime outbreaks on many streets in the more thug-filled areas. The Big Hero 6 had already had to stop already six botfights, two muggings, and catch two teams of bank robbers. They were all exhausted, sweating in their suits, and panting softly.

Hiro glanced at Honey Lemon, who looked slightly dizzy. When they were trying to catch the bank robbers, one of the robbers had tried to release tear gas on them. Honey Lemon had accidently inhaled some, and passed out. By the time she woke up, the police had been driving urgently up the road, so they had had to leave quickly.

She still seemed a little tired, and the hot suit and large amount of crimefighting earlier hadn't helped. Honey brushed it off though, saying it was alright. Hiro was still slightly worried about her, though.

The rest of the team - to Hiro's relief - seemed only tired, nothing else.

"Baymax, what time is it?" Hiro asked the robot. He hadn't really bothered to install a watch into his suit, so Hiro had been forced to rely on Baymax to tell him the time, since Tadashi had installed a watch on him.

"The current time of San Fransokyo, Japan is eleven forty-five , Hiro," Baymax informed him. "You have missed your curfew by seventy-five minutes."

Hiro cursed under his breath.

"Now Tadashi's gonna think I'm bot-fighting again." Hiro said to himself.

He then leaned closer to Baymax's head. "Baymax, can you scan the city to see if there's any more crimes out there?"

"Scanning city, now."

After several moments of silence, with the exception of the wind in his ears, Baymax finally answered.

"There appears to be no crime outbreaks as of now."

"Good..." Hiro whispered to himself. He then put a finger on the button to turn on his mic. in his intercom.

"Alright guys, that's enough crime-fighting for tonight." Hiro smiled in amusement at the moans of relief coming from the speakers.

"Great, I can finally get some rest!" Honey Lemon said.

"Yeah, and I can finally start updating my bike," Gogo agreed.

"You sure that's all the outbreaks for tonight?" Wasabi inquired Hiro, glancing at him.

"Yep, Baymax confirmed it-"

"Hiro, it appears a building in front of us has been violated and is being robbed," Baymax observed.

The team all barely, but surely, heard Baymax and looked ahead. Baymax was definantly right: a tall office building they were approaching had many windows, in which they could see masked men (or women) with guns, running through the bland halls and shooting at unknown targets.

"'Kay guys, time to stop a massacre," Hiro told his teammates through his intercome. In the dark he could barely see Wasabi, Honey Lemon, and Gogo scowling towards the air, and Hiro could tell Fred was glaring inside his suit.

"Aw, so I have to miss the premiere of the new Young Justice remake?" Hiro heard Fred mumble through the intercome. He smiled and decided not to answer, Fred already knew the answer.

They raced to the building, trying to get there as fast as they could. They all really wanted to just get home at that point. Hiro and Baymax landed on top of the building, while Honey Lemon threw her balls of chemical goo to make a rope and climb up to the top. Gogo climbed with Honey Lemon, and Fred jumped from window sill to window sill upwards. Wasabi stood at the bottom of the building, however.

"I'll go in and hold them off while you guys come up with a plan," Wasabi told them through the intercom. He gave them a brief nod, then hesitantly took a step forward, knowing that his life was in the balance, and then gathered some courage and ran inside.

"Hiro what's the plan?" Gogo asked immediatly as she stood on the building. Everybody was impatient as Hiro thought for a moment, their friend Wasabi's life was at risk if they waited too long.

After a moment Hiro look up at them.

"We should probably just run in, and knock as many guys out as we can, and try not to get hurt." Hiro couldn't really think up a well-thought out plan at the moment, due to his tiredness.

The team nodded.

"Okay... Wasabi, did you get that?" Gogo asked through the intercom.

"Got it." They heard Wasabi's voice say. Suddenly, they all jumped as they heard a loud gunshot echo through the intercom, and Wasabi's yelp, and Wasabi's line cut off.

Gogo's eyes widened in shock and fear, and she quickly pressed the button on her mic.

"Wasabi! Do you hear me? Are you okay!?" Gogo cried. Her usually cool and collected attitude was gone now, and now there was just an angry panic in her eyes.

"Y-yeah, I'm fine," Wasabi's shaky voice came out, loud and clear through intercom. "I just got shot at. Luckily, it hit my chest plate where my suit is the hardest, so yeah, I'm good."

Everybody sighed silently in relief, before Gogo told Wasabi,"Well, we're coming in, so you'll have help in right about... now."

Honey Lemon typed up a code on her purse, which spat out a purple- pink ball. She quickly threw it on the ground of the roof, and Fred suddenly shot fire at it. They all took several quick and large steps back before the chemical ball blew-up. It was a rather small explosion, but was still big enough create a hole in the ceiling big enough for them to jump through.

Once they had all landed inside the building, immediately gunshots echoed off the walls as bullets came from all directions. Some hit Hiro's suit and bounced off, not hurting him (Just scaring the crap out of him). Hiro quickly jumped to the ground and crawled as fast as he could to cover.

Hiro jumped under a little desk with a computer on it. He was nearly hyperventilating by now, for it had been months since he'd been so close to death like that. He looked down at his chest plate to see little dent marks from where the bullets had hit it. When he got back from this, Hiro was planning on updating the armor so it would be _much_ stronger.

Hiro peered over the desk to where the shooters. He spotted about fifeteen beings standing at different areas in the room. They all wore white masks and held small (But powerful) handguns. He scanned the room urgently for any sign of his friends. Hiro was relieved to find Gogo and Honey Lemon hiding under another desk and throwing their discs and chemical balls at them. Hiro then spotted Baymax and Fred standing in the middle of the room, where Fred throwing random objects at anybody who approached them, and Baymax just standing there looking around, most likely for Hiro.

Hiro watched as the bullets sailed through the air towards Baymax, hitting Baymax, but bouncing right off because of his armored suit.

Hesitantly, Hiro started crawling toward Honey Lemon and Gogo, trying his best to make himself as unnoticable as possible, though it's pretty hard when you're a fourteen year-old in a bright red and purple mechanical suit.

"Oh, there you are!" Honey Lemon smiled as she glanced at him. She then went back hurriedly typing different codes into her purse and throwing chemical balls at their attackers. "I was starting to think that you were hurt or something-"

"Guys! Guys, are you in the building, yet?" Wasabi's urgent voice sounded through their communicators. "I've knocked out most of the guys on the first, second, third, fourth, and fifth floor!"

"Yeah we're in," Hiro informed Wasabi, checking out a map of the building that was pinned to a white board sitting near their hiding place. "We're on the... sixth floor!'

"Okay good, I'm coming up," Wasabi told them. "How many guys are up there?"

"About fifeteen, I think."

"Okay."

Suddenly, Fred ran over, noticing his friends.

"What did I miss?" he asked.

"Not much," Hiro replied. "But Wasabi's coming."

Suddenly, the small elevator on the other side of the room opened, and Wasabi jumped in the room. He used his lazers to sloppily dodge bullets, and used them to sheild his face as he ran towards his friends.

"Okay, there's a lot more people up here than there was on the last five floors," Wasabi commented as he kneeled down next to his friends. "What do think the reason is behind this robbery?"

"I don't know," Hiro said. "It might just be some twisted men being twisted men?"

"Or women." Gogo said as she threw a disc.

"Maybe," Wasabi said. "How do you think we're gonna knock them out?"

"We could probably use some of Honey Lemon's chemicals?" Gogo suggested as she took a short break from throwing discs. "She does have some that can knock out people, right?"

"Already on it." Honey assured them as she typed for about the hundredth time that night a code into her purse. A greenish-bluish ball popped out.

"Cover your nose and mouths!" Honey Lemon told her friends. They all quickly obeyed her as Honey threw the ball. The ball sailed through the air, and when it hit the ground a bluish-green fog instantly emitted from it. The fog encased the room, muffling any sound made in there.

Hiro heard the sounds of bodies dropping to the ground with small, tired groans. Once the fog cleared, Hiro looked around. It looked like everyone had passed out except him and his friends.

"I think they're all knocked out." Hiro stated. The teens all nodded in agreement and got up from their hidding spot.

"I'll get the police to come here." Gogo said as she pulled out her phone and started to dile the number.

Suddenly, the sound of another gun shot reverberated throughout the room as a bullet sailed through the air towards Gogo. Wasabi was quick to spring into action push her out of the way. They both fell to the ground with a yelp.

They all gasped suddenly, as a figure appeared out of nowhere, and ran up the stairs towards the roof of the building. Gogo stood up, panting from shock. "Let's go get him-"

Hiro quickly grabbed her arm, saying, "No I'll get him, you guys call the police."

Hiro held out his hand to Honey Lemon, who seemed to know exactly what he wanted. She quickly typed a code into her purse and grabbed out the greenish-blue ball and plopped it in his hand.

"Be careful." She warned him. Hiro nodded and ran after the man.

He ran up the fire escape, feeling butter-flies in his stomach. For the first time, he was going to take down a guy all by himself!

Once Hiro reached the roof of the building, he quickly scanned the area. There seemed to be nobody in sight, and everything was silent. All there was was random pieces of furniture. This must have been a building to some kind of furniture company. Hiro turned to the right of the roof, just in time to see a dark figure standing there, turned away from him.

Hiro quickly crept up behind the guy, ready tackle him to the ground. He then jumped at the figure, and tried to grab at it. He caught something, but it did not feel like a person. In fact, it felt like a -

Hiro looked down to see a dark coat in his hands. Hiro's eyebrows shot up in surprise. He looked behind himself to see a coat stand standing where the figure had. Hiro shakily stood up, knowing in fear that the man had tricked him, and could attack him at minute.

Suddenly, a gunshot could be heard, and a bullet hit Hiro's suit, denting it. Hiro's head snapped up, just in time to see a man in a mask. Unlike the other shooters, this one didn't wear a black jacket.

The man shot at Hiro several more times, until suddenly-

The next bullet hit the button on his helmet that was made turned off the suit, and the suit suddenly opened up, and it came off of Hiro, and mechanically transformed into a tiny red and purple cube behind him, just like it did every time he pressed the button. Hiro stared, horrified.

The man could easily kill him now, just with one gunshot. All he was wearing was a simple t-shirt and kackies.

At that moment, to add more to Hiro's horror, he suddenly realized that he was standing on the edge of the building, and the drop was about sixty feet below...

He was screwed. Just very, very screwed.

Hiro could tell that the man was smiling behind his mask as he stalked towards Hiro.. He then lifted his gun, and - WHAM! - the last thing Hiro heard before the pain in his chest was the gunshot reverberating throughout the night. The pain was almost blinding, and Hiro let out one last scream of pain before he tumbled over the edge of the roof to his doom.

The man smirked heavily as he tossed the purple and red cube after Hiro, just so everyone would know he had just killed the leader of Big Hero 6 single handedly. He smirked even more when the other four kids and the robot came up just in time to see their friend tumbling. But he wasn't smiking when the girl in orange and purple grabbed another one of her chemical balls from her purse and threw it at him, which let a gas that knocked him out.

* * *

There was a great tension in the air of the small electric car as Aunt Cass and Tadashi drove through the dark street of San Fransokyo. Tadashi looked over at Aunt Cass hesitantly, and took notice in the fuming glare she gave the air. He didn't blame her, though, knowing full well the reason behind the glare was because of the information he had just given her.

Since Hiro had been home so late, Tadashi had started worrying it was a bot-fight. Tadashi had tried to go searching for Hiro on his own, but Aunt Cass, who furious at Hiro for bot-fighting again, insisted on going along.

No sound was made in the car, except for the soft buzz of the car gliding along the road. They had finally finally reached the sketchy part of San Fransokyo, where thugs were always around and bot-fights usually took place.

After about two hours of searching and asking around (asking the most safest-looking people) Tadashi and Cass had finally last most of their hope. Praying that Hiro would be home when they got there, they defeatedly decided to drive back to the ca`fe.

As they drove in silence, Tadashi took notice in the building they were nearing. It was one of the Harry's House Furniture office buildings. He had gone on a field trip there when he was eight. It was pretty bland and boring, and later that day got worse when he found out his parents had died.

It had been a pretty horrible day, and seeing that building brought back those memories, so he decided to look away from it, and focus his attention something else, like the quiet music playing on the radio.

Suddenly, and without warning, something from above crashed into the top of the car, effectively denting it. The car suddenly swirved to the side, for Aunt Cass accidently screwed up the wheel when she jumped from the surprise of the impact. Aunt Cass slammed on the breaks of the car to stop them from crashing into anything.

For a second they stood there in shock, panting, before Tadashi regained his senses sprang out of the car immediately to see what had fallen on their car. To his horror, he saw a figure, trembling violently, and lying in a pool of dark, scarlet, blood.

"Holy ****!" Tadashi cursed as he ran up to the figure. He dropped to his knees beside it, panicking. "Are-are you okay?! Can you-can you hear me?!"

He couldn't see who it was properly, due to the person lying face-down on its stomach, but he could see the person was a very small male, and had a messy mop of raven hair that sat on its head, which looked vividly familiar.

"Tada-d-dashi..." the voice was weak, full of pain, and had a sob clinging to it. Horrible realization hit Tadashi square in the face like a brick: this boy that had fallen onto the car - who was dying infront of him - was Hiro.

The boy turned over, to reveal Hiro's face, which had some blood on it and lots of scratches and bruises.

"Oh god, H-Hiro no!" Tadashi sobbed as he quickly wrapped his arms around his brother and pulled him to his chest. He could hear a crowd of people crowding around them, now, and he heard some people calling the police. Tadashi couldn't care less now, he was very busy sobbing into his brother's hair. Suddenly, a small hand placed itself on Tadashi's shoulder. Tadashi looked up miserably to see it was Aunt Cass who had layed her hand on his shoulder.

Tears were running down her cheeks, shining from the lights of the street. Her face showed sadness and despair as she watched her nephews. A little cube suddenly landed on the ground next to Tadashi and Hiro. Once it hit the ground, the cube transformed into a mechanical red and purple suit, which looked almost exactly like the suit the leader of Big Hero 6 wore...

Another realization hit Tadashi that night: Hiro was the leader of Big Hero 6. How hadn't he realized it before? The boy and Hiro shared so many physical characteristics: Hiro was the short like him, and had dark hair that Tadashi usually saw inside the helmet, and the robot, could have been Baymax. Hiro did claim that Baymax was 'destroyed' on the night of the fire... He could have told Tadashi that so Tadashi wouldn't have known that the robot was Baymax...?

If Hiro was the leader of Big Hero 6, then who were his teammates?

Suddenly, the doors to the office building flew open with much force, and out came the other four members of the Big Hero 6. They ran up to Hiro and Tadashi, and the girl in the orange and pink dropped to her knees.

"Hiro..." Tadashi heard her mutter sadly. Suddenly, Tadashi realized that this girl was his best friend, Honey Lemon. Shock struck him even more as he looked to the girl in the yellow and black.

Gogo...

The boy with lazer arms.

Wasabi...

Tadashi was pretty sure the person in the dinosaur suit was Fred, he had always asked Honey Lemon to create a formula to make him fire-breathing dragon...

That left the giant flying robot clad in red and purple armor.

Baymax...

Anger started to flare up in Tadashi as he realized his friends had let his brother get killed like that. They did let him fight crime, apparently, and were there when he fell...

Tadashi jumped as he noticed Hiro's trembling hand reaching toward him.

"'D-dashi..." Hiro stuttered out. "I-I'm sorry... Nissan..."

The boy twisted sluggishly around, his face contorted in agony. Tadashi wiped the crystal-like tears from his face.

"It's okay outoto, it's okay..." Tadashi assured his brother, even though it definantly was not. He put himself out in danger like that... How could he? Through his anger, though, Tadashi still couldn't scold him for it now, not at a moment like this.

"I love, Hiro. I love you." Tadashi hugged his brother closer. He could feel the warm, sticky blood soaking his own clothes, but didn't care, for his brother was dying, right in his arms.

"I-I love you, t-too..." Hiro small voice croaked out from his chest.

Finally, Tadashi heard and felt Hiro let out one last breath against his chest, and he fell limp in his arms. Tadashi stood there, silent and in shock, his brother's death not quite sinking in.

My brother's dead... My bother's dead... Oh god, _my brother's dead_!

Finally, heart-wrenching sobs broke from Tadashi, a fresh and heavy wave of warm tears spilling from his eyes as he hugged his brother's lifeless body. Hiro was gone now, and there was nothing he could do about it.

"Hiro, I'm so sorry, I'm so, so sorry..." Tadashi mumbled over and over again, hoping he'd hear his brother's voice reply back, but he knew it wouldn't, and never will again.

"T-Tadashi, we're so sorry..." Honey Lemon's voice piped up from the side of him. She put a careful hand on his shoulder, trying to give him comfort. Most of the team had tears falling from their eyes now, even Gogo.

 _This is their fault..._

Tadashi angrily slapped Honey Lemon's hand away, dropping Hiro's body down onto his lap.

"Don't touch me!" Tadashi raged. "This is your guy's fault! You let him crime fight, and never bothered to think about the risks, and you fought alongside him! How could you guys do that?!"

The team all had hurt looks on their faces, but knew full well that Tadashi was right: they fought crime along with a fourteen year-old, and now because of their stupidity for continuing it, they payed the ultimate price.

They bowed their heads, not daring to look Tadashi in the eye. It was their fault, and they would forever feel guilty about it.

The police and ambulance arrived, and they ordered people to clear out of the crime-scene. Everybody was heart-broken that night, and it was hard for anybody who witnessed Hiro's death to sleep. Everybody knew they had lost somebody that would have done great things, and now that person would never get to shine their light into the world.

* * *

 _Her greatest mistake,_ Gogo thought to herself. She should have gone with him to catch that guy, but now it's too late.

She, Honey Lemon, Wasabi, and Fred stood in front of Hiro's grave, shivering slightly from the wind and rain. They didn't bother to leave to get warm, though, for they knew they deserved to be cold, perhaps even freeze to death, they felt.

A week had passed since that night, that terrible night.

Their Greatest Mistake, they called it.


End file.
